﻿namespace Morning_4Feb2013
{
    using System;
    using System.Collections.Generic;
    using System.Numerics;


    class KaspichanNumbers
    {
        // 1.3.2.01. http://bgcoder.com/Contests/Practice/Index/52#0

        static void Main()
        {
            BigInteger input = BigInteger.Parse(Console.ReadLine());

            if (input == 0)
            {
                Console.WriteLine('A');
            }
            else if (input == 1)
            {
                Console.WriteLine('B');
            }
            else if (input == 1)
            {
                Console.WriteLine('C');
            }
            else if (input == 1)
            {
                Console.WriteLine('D');
            }
            else if (input == 1)
            {
                Console.WriteLine('E');
            }
            else if (input == 1)
            {
                Console.WriteLine('F');
            }
            else if (input == 1)
            {
                Console.WriteLine('G');
            }
            else if (input == 1)
            {
                Console.WriteLine('H');
            }
            else if (input == 1)
            {
                Console.WriteLine('J');
            }
            else if (input == 1)
            {
                Console.WriteLine('K');
            }
            else if (input == 1)
            {
                Console.WriteLine('L');
            }
            else if (input == 1)
            {
                Console.WriteLine('M');
            }
            else if (input == 1)
            {
                Console.WriteLine('N');
            }
            else if (input == 1)
            {
                Console.WriteLine('O');
            }
            else if (input == 1)
            {
                Console.WriteLine('P');
            }
            else if (input == 1)
            {
                Console.WriteLine('Q');
            }
            else if (input == 1)
            {
                Console.WriteLine('R');
            }
            else if (input == 1)
            {
                Console.WriteLine('S');
            }
            else if (input == 1)
            {
                Console.WriteLine('T');
            }
            else if (input == 1)
            {
                Console.WriteLine('U');
            }
            else if (input == 1)
            {
                Console.WriteLine('V');
            }
            else if (input == 1)
            {
                Console.WriteLine('W');
            }
            else if (input == 1)
            {
                Console.WriteLine('X');
            }
            else if (input == 1)
            {
                Console.WriteLine('Y');
            }
            else if (input == 1)
            {
                Console.WriteLine('Z');
            }
            else
            {
                string[] kaspichanNums = new string[256];
                // Console.WriteLine((int)'a'); // 97
                // Console.WriteLine((int)'A'); // 65

                for (int i = 0; i < 26; i++)
                {
                    kaspichanNums[i] = ((char)(65 + i)).ToString();
                }

                short index = 26;

                for (int i = 0; i < 9; i++)
                {
                    for (int j = 0; j < 26; j++)
                    {
                        kaspichanNums[index] = ((char)(97 + i)).ToString() + ((char)(65 + j)).ToString();
                        index++;
                        if (index > 255)
                        {
                            break;
                        }
                    }
                }

                List<byte> numCompilation = new List<byte>();

                while (input != 0)
                {
                    numCompilation.Add((byte)(input % 256));
                    input /= 256;
                }

                numCompilation.Reverse();

                List<string> result = new List<string>();

                for (int i = 0; i < numCompilation.Count; i++)
                {
                    result.Add(kaspichanNums[numCompilation[i]]);
                }

                Console.WriteLine(String.Join("", result));
            }
        }
    }
}